Viktor Bout sought to have his 2011 conviction and 25-year prison sentence for conspiracy to kill American citizens and illegally selling arms including assault rifles, anti-aircraft missiles, and other high-powered weapons on the black market, overturned.

However, the U.S. 2nd Circuit Court of Appeals denied his motion on Monday.

The three-judge panel dismissed arguments by Bout’s attorneys, who claimed their client’s prosecution, was tainted after evidence surfaced showing one of his supposed co-conspirators was working for the U.S. government.

His attorneys argued their client could not have conspired Andrew Smulian, a former business associate who testified against Bout during his trial because Smulian already was already working an informant for the DEA.

“Merchant of Death” arms dealer Viktor Bout after he was extradited back in 2010.

The appellate court judges wrote in Monday’s decision that the agency “recruited Smulian as a way to get to Bout,” The UPI reported.

“We do not agree with this ruling; the U.S. Supreme Court is the sole possible further move,” Bout’s lawyer Alexei Tarasov told Russia’s state-owned Tass.

Viktor Bout used connections he maintained within the former Soviet Republic to build a worldwide air cargo operation, which included a fleet of airplanes, to sell and deliver weapons to terrorist organizations and two-bit despot dictators around the world.